Speech Perception and High Cognitive Demand

BEHAVIORAL

Auditory-cognitive training paradigm

The investigators developed an American English version of the Nottingham (UK) PLUS training paradigm in which listeners are asked to focus and listen to one speaker while ignoring another speaker. The paradigm is designed to optimally enhance the possibility of benefit: an adaptive procedure is employed to train each individual at their own level to make the task challenging. A short-term memory component, in which listeners are asked to remember what a designated speaker said two sentences prior, was added to the auditory training paradigm to make the task more challenging. Participants will be asked to recall the keywords of the to-be-attended speaker. The sentences will be presented in a two-down one-up adaptive procedure in which the ratio of the levels of the to-be-attended and to-be-ignored speaker will be adjusted based on the correctly recalled key words.

BEHAVIORAL

Auditory training paradigm

The investigators developed an American English version of the Nottingham (UK) PLUS training paradigm in which listeners are asked to focus and listen to one speaker while ignoring another speaker. The paradigm is designed to optimally enhance the possibility of benefit: an adaptive procedure is employed to train each individual at their own level to make the task challenging. Participants will be asked to recall the keywords of the to-be-attended speaker. The sentences will be presented in a two-down one-up adaptive procedure in which the ratio of the levels of the to-be-attended and to-be-ignored speaker will be adjusted based on the correctly recalled key words.

Change in speech-in-noise perception

Time frame: Week 1-2 (pretest) and Week 5-6 (posttest)

In the Quick Speech-in-noise task (QSIN). Participants listen to a target female speaker in babble across six sentences (i.e., one list) presented at different signal-to-noise ratios (SNRs). Each sentence has five target words that participants are asked to repeat at the end of each sentence. Within each list, the first sentence is played with a 25 dB SNR and SNR decreases as the list progresses in increments of 5 dB., with the final sentence played at 0 dB. The average SNR score is calculated across several lists. The average SNR score is calculated across several lists. Scores range from -4.5 to 25.5 dB. Higher scores indicate greater SNR loss (i.e., worse hearing).

Audiobook - Change in pupillary response

Time frame: Week 1-2 (pretest) and Week 5-6 (posttest)

During an audiobook listening task, pupil dilations are recorded as an objective measure of listening effort, with larger pupil dilations indicating increased listening effort. Change in pupil dilations at pre and posttest (before and after training, respectively) will be measured. In the audiobook listening task, audiobook segments will be presented to participants at signal-to-noise ratios (SNRs) of quiet, 0 dB, -6 dB, and in babble (with four background speakers). Participants listen to each audiobook segment three times.

Audiobook - Change in magnetoencephalography (MEG) temporal response function

Time frame: Week 1-2 (pretest) and Week 5-6 (posttest)

During an audiobook listening task, MEG neural activity will be recorded. The investigators will evaluate change in the temporal response function (TRF). The TRF relates how the brain responds to acoustic stimuli and can be viewed as evoked responses to the continuous speech. Audiobook segments will be presented to participants at signal-to-noise ratios (SNRs) of quiet, 0 dB, -6 dB, and in babble (with four background speakers). Participants listen to each audiobook segment three times.

Change in Magnetoencephalography (MEG) stimulus reconstruction accuracies and integration window analysis

Time frame: Week 1-2 (pretest) and Week 5-6 (posttest)

During an audiobook listening task, MEG neural activity will be recorded. The investigators will measure how far the neural response tracks the speech stimulus by stimulus reconstruction accuracies and how the stimulus reconstruction accuracy builds up over time by integration window analysis. Audiobook segments will be presented to participants at signal-to-noise ratios (SNRs) of quiet, 0 dB, -6 dB, and in babble (with four background speakers). Participants listen to each audiobook segment three times.

Audiobook - Change in frequency following response (FFR)

Time frame: Week 1-2 (pretest) and Week 5-6 (posttest)

During an audiobook listening task, MEG neural activity will be recorded. The investigators will measure change in the FFR. The FFR is a measure of neural activity in response to a sound and serves as a measure of neural sound encoding. Larger FFR amplitudes indicate greater representations of an auditory stimulus. Audiobook segments will be presented to participants at signal-to-noise ratios (SNRs) of quiet, 0 dB, -6 dB, and in babble (with four background speakers). Participants listen to each audiobook segment three times and after each repetition.

Audiobook - Change in Magnetoencephalography (MEG) network localized granger causality

Time frame: Week 1-2 (pretest) and Week 5-6 (posttest)

During an audiobook listening task MEG neural activity will be recorded. The investigators will measure the network localized granger causality (NLGC) to measure the networked activity of the cortex. Audiobook segments will be presented to participants at signal-to-noise ratios (SNRs) of quiet, 0 dB, -6 dB, and in babble (with four background speakers). Participants listen to each audiobook segment three times and after each repetition.

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A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

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Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

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Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.